Berberis vulgaris (European barberry) is a shrub in the family Berberidaceae, native to central and southern Europe, northwest Africa and western Asia; it is also naturalised in northern Europe, including the British Isles and Scandinavia, and North America.
It is a deciduous shrub growing up to 4 m high. The leaves are small oval, 2-5 cm long and 1-2 cm broad, with a serrated margin; they are borne in clusters of 2-5 together, subtended by a three-branched spine 3-8 mm long. The flowers are yellow, 4-6 mm across, produced on 3-6 cm long panicles in late spring. The fruit is an oblong red berry 7-10 mm long and 3-5 mm broad, ripening in late summer or autumn; they are edible but very sour, and rich in Vitamin C.
The plant is both poisonous and medicinal. The plant, except for its fruits and seeds, is mildly poisonous. Its most potent agent is berberine, which is also known to have a number of therapeutical effects. In Europe, the berries are traditionally used for making jam. In southwestern Asia, especially Iran, where they are called zereshk (زرشک), the berries are used for cooking, as well as for making jam. It is an intermediate host for Puccinia graminis (black rust), a rust disease of wheat. Wheat farmers had accused barberries of spreading rust as early as 1660, but were derided as superstitious by the jam makers. The matter was not settled scientifically until 1865. Because of the impact of this disease on wheat crops, cultivation of European barberry is prohibited in many areas.